Electrospun Ce-Mn oxide as an efficient catalyst for soot combustion: Ce-Mn synergy, soot-catalyst contact, and catalytic oxidation mechanism.
Electrospun Ce-Mn oxide as an efficient catalyst for soot combustion: Ce-Mn synergy, soot-catalyst contact, and catalytic oxidation mechanism.
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DOI：
10.1016/j.chemosphere.2023.138995
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发表时间：
2023-09-01
期刊：
影响因子：
8.8
通讯作者：
Ye, Daiqi
中科院分区：
文献类型：
--
作者：
Liao, Yuxi;Liu, Peng;Ye, Daiqi
提高接触效率和提高本征活性是获得高效碳烟燃烧催化剂的两个有效策略。本文采用静电纺丝法合成纤维状Ce-Mn氧化物，具有很强的协同效应。前驱体中PVP的缓慢燃烧和纺丝溶液中高溶解度的醋酸锰促进了纤维状Ce-Mn氧化物的形成。流体模拟清楚地表明，细长和均匀的纤维提供了更多的交织大孔捕获烟灰颗粒比立方体和球体做。因此，静电纺丝Ce-Mn氧化物表现出比参比催化剂更好的催化活性，包括通过共沉淀和溶胶-凝胶法制备的Ce-Mn氧化物。结果表明，Mn 3+取代萤石型CeO 2，通过促进Mn-Ce电子转移增强了还原性，通过削弱Ce-O键提高了晶格氧的迁移率，并诱导了氧空位，使O2活化.理论计算表明，Ce 3 +-Ov（氧空位）的形成能较低，有利于晶格氧的释放，而较高的还原电位有利于O2对Ce 3 +-Ov（氧空位）的活化。由于上述Ce-Mn协同作用，CeMnOx-ES比CeO 2-ES和MnOx-ES显示出更多的活性氧物种和更高的储氧能力。理论计算和实验结果表明，吸附态O2比晶格氧活性高，催化氧化主要遵循Langmuir-Hinshelwood机理。研究表明，静电纺丝是一种制备高效铈锰氧化物的新方法。
Increasing the contact efficiency and improving the intrinsic activity are two effective strategies to obtain efficient catalysts for soot combustion. Herein, the electrospinning method is used to synthesize fiber-like Ce-Mn oxide with a strong synergistic effect. The slow combustion of PVP in precursors and highly soluble manganese acetate in spinning solution facilitates the formation of fibrous Ce-Mn oxides. The fluid simulation clearly indicates that the slender and uniform fibers provide more interwoven macropores to capture soot particles than the cubes and spheres do. Accordingly, electrospun Ce-Mn oxide exhibits better catalytic activity than reference catalysts, including Ce-Mn oxides by co-precipitation and sol-gel methods. The characterizations suggest that Mn3+ substitution into fluorite-type CeO2 enhances the reducibility through the acceleration of Mn-Ce electron transfer, improves the lattice oxygen mobility by weakening the Ce-O bonds, and induces oxygen vacancies for the activation of O2. The theoretical calculation reveals that the release of lattice oxygen becomes easy because of a low formation energy of oxygen vacancy, while the high reduction potential is beneficial for the activation of O2 on Ce3+-Ov (oxygen vacancies). Due to above Ce-Mn synergy, the CeMnOx-ES shows more active oxygen species and higher oxygen storage capacity than CeO2-ES and MnOx-ES. The theoretical calculation and experimental results suggest that the adsorbed O2 is more active than lattice oxygen and the catalytic oxidation mainly follows the Langmuir-Hinshelwood mechanism. This study indicates that electrospinning is a novel method to obtain efficient Ce-Mn oxide.